The WHOIS database contains basic information about owners of .com, .net and .org domains, including names, addresses and phone numbers.

Beales' testimony comes as Congress considers a bill that would make it a federal crime to submit false data when registering a domain name.

"It is hard to overstate the importance of accurate WHOIS data to our Internet investigations," Beales said. "In all of our investigations against Internet companies, one of the first tools FTC investigators use to identify wrongdoers is the WHOIS database.

"We cannot easily sue fraudsters if we cannot find them. We cannot even determine which agency can best pursue them if we are unable to figure out the country in which they are located," he continued.

The FTC said Wednesday that it endorses the elimination of blank or incomplete registration forms and false information, and requiring registrars to suspend domain registration for failure to correct inaccurate contact information.

The agency also hopes that registry managers will work with registrars in other countries to improve accuracy of WHOIS data for non-U.S. domains.

Advocates of increased privacy rights have opposed the bill, saying that people may have legitimate reasons for placing anonymous data on the registries, such as avoiding spam.